NOT_AVAILABLE can be returned if JsonParser
implementation can not currently return the requested
token (usually next one), or even if any will be
available, but that may be able to determine this in
future. This is the case with non-blocking parsers --
they can not block to wait for more data to parse and
must return something.

Placeholder token returned when the input source has a concept
of embedded Object that are not accessible as usual structure
(of starting with START_OBJECT, having values, ending with
END_OBJECT), but as "raw" objects.

Note: this token is never returned by regular JSON readers, but
only by readers that expose other kinds of source (like
JsonNode-based JSON trees, Maps, Lists and such).

VALUE_NUMBER_INT is returned when an integer numeric token is
encountered in value context: that is, a number that does
not have floating point or exponent marker in it (consists
only of an optional sign, followed by one or more digits)

VALUE_NUMBER_INT is returned when a numeric token other
that is not an integer is encountered: that is, a number that does
have floating point or exponent marker in it, in addition
to one or more digits.